Abstract

Measurements of the rate of ambient air entrainment by axisymmetric
diffusion flames suggest that entrainment occurs at a wrinkled laminar
flame front in the lower regions of visible flame (Ref. 1). Entrainment
of such flames requires a solution of the axisymmetric steady laminar
diffusion flame which does not yield a self-similar solution. If one
then considers the simple case of steady plane diffusion flame in
semi-infinite fuel and oxidizer media separated by a flame sheet, an
exact similarity solution can be obtained from equations of motion,
energy and species conservation equations. This solution can also
incorporate the differences in fuel and oxidizer densities resulting
from either molecular weight differences or the temperature differences
of oxidizer and fuel media. This problem was treated by G. C. Fleming
and F. E. Marble to investigate the stability of such a flame front to
periodic disturbances (Ref. 2). Inspired by their study, we chose to
develop an integral solution to the same problem by appropriate selection
of velocity, temperature and species profiles.